This invention relates to the removal of burrs at the exit end of drilled holes, especially in manufactured metal parts, and more particularly to a method of using a high power laser beam to remove burrs at the exit end of such holes.
In the manufacture of machinery of various kinds it is often necessary to provide intersecting passageways in various metal parts thereof. Often, one of such passageways will receive a plunger or shaft and the passageway intersecting therewith will provide for the flow of lubricating oil or other fluid thereto.
In any event, such intersecting passageways are usually formed by forming a passageway into the manufactured metal part and subsequently drilling a hole into the metal part which intersects the passageway. It is a well-known fact that when a hole is drilled through a surface of a metal part, a thin protruding rough rim or edge will be formed about the hole in such surface due to the fact that a portion of the drill will tend to exit from the metal part extruding some small amount of incompletely cut metal from the hole in the process. Such a thin protruding rim or edge is known as a "burr" and will tend to be formed at the junction of a drilled hole with a previously formed passageway in a metal part.
It is, of course, necessary to remove any such burrs from the interior of the passageway, since such burrs will change the internal dimensions thereof and interfere with the passage of fluids, shafts or plungers through the passageway which may be a first drilled hole. In the prior art, various time consuming and expensive mechanical methods have been used to remove such burrs. For example, where the passageway is formed by a first drilled hole, the drill may be passed into it a second time or other special tools may be used within the passageway to mechanically remove the burrs. There is, of course, the danger that the material which forms the burr in the passageway will not be removed but simply forced into a different burr inside the end of the drilled hole, as well as the danger that the internal dimensions of the passageway will be spoiled by misalignment of the drill or other tool therewith. If the material which forms the burr is not removed but simply relocated, then there is the danger that some or all of such material will subsequently break away and cause damage somewhere else in the machine.
It is the basic object of this invention to provide a method for quickly and efficiently removing burrs from the junction of drilled holes with a surface or passageway in metal parts, which method will result in the complete removal of material which forms such burrs without danger of spoiling the surface or the internal dimensions of the passageway or drilled holes.